Hacker Chronicles 2/HACKER2.BIN/1326.ICOMCIV.TXT

Text File | 1991-03-21 | 24KB | 553 lines

From: [e-mail] (John McHarry)
Newsgroups: rec.radio.amateur.misc
Subject: Icom CI V spec
Summary: Here is a good description of the spec.
Keywords: Icom, CI V
Message-ID: <[e-mail]>
Date: 17 Mar 91 22:29:16 GMT
Sender: [e-mail] (News Service)
Organization: The MITRE Corporation, Bedford MA
Lines: 539
Nntp-Posting-Host: mwunix.mitre.org

N6GN sent me this after my last post.

Date: Fri, 15 Mar 91 11:21:52 -0800
From: Glenn Elmore <[e-mail]>
Hope this helps...

de n6gn


                   THE ICOM CI-V COMPUTER INTERFACE

                       E. R. (Randy) Cole, KN6W
                        3100 Ocean Park Blvd.
                       Santa Monica, CA  90405

                Copyright (c) 1986,1987 Edwin R. Cole

(This document may be freely copied and distributed provided the above
copyright notice is included on all copies. It may not be sold by
anyone except the author)

Have you bought a new radio lately?  If you have, you probably noticed
that it came with an increasingly common feature -- a computer
interface.  Actually, radios with computer interfaces have been around
since 1976, when the ICOM IC-211 and 245 appeared on the scene with a
computer interface that allowed remote control of the radio's
frequency.  The IC-701, introduced in 1978, used the same interface.
Since then ICOM has produced the IC-720/251/255/260/451 series and the
IC-R71/751/271/471/1271 series, each with a different type of computer
interface.  Both Yaesu and Kenwood now have their own interfaces for
their families of radios.  The various interfaces are described in [1]
- [5].

ICOM recently introduced a new type of computer interface, called the
CI-V Communication Interface System.  The CI-V interface first
appeared on the IC-735, and is now also found on the IC-275, IC-375,
IC-475, IC-575, IC-761 and IC-R7000.  The functions performed by the
radios via this new interface are generally the same as those possible
via the interface for the R71/751/271/471/1271 series [4], plus a few
enhancements.

A recent Ham Radio article [6] provides a very simple (one resistor)
interface and an elaborate Basic program for controlling the IC-735
with a Commodore 64.  That same interface can be used to control any
of the ICOM CI-V radios using a C64.  However, there are significant
differences between radios, especially in the case of the R7000.  The
author has tested the IC-735, IC-275, IC-475, and IC-R7000.  This
article describes how to control any of the current ICOM CI-V radios.
A short Basic program for the IBM PC is included to demonstrate use of
the interface.


THIS ONE IS DIFFERENT

Ho hum, you say, yet another interface.  Big deal; what we really need
is some standardization.  That's certainly true, but the latest ICOM
interface is altogether different from all the rest.

Picture this:  You can have up to 15 radios and up to 254 computers,
all connected in parallel to the same two-wire bus.  Any computer can
control any radio.  In fact, radios can control each other.  You can
even have more than one of the same type of radio on the bus.
Commands are guaranteed to get through, even if different computers
decide to send commands to different radios at exactly the same time.

How is it done?  The new ICOM interface is a CSMA/CD bus.  The letters
stand for Carrier Sense Multiple Access with Collision Detection, and
the technique has been used for computer networks (like the
Ethernet(tm)) for years.  Multiple access refers to the fact that
there can be many devices (computers and radios, in this case) on a
single bus.  Carrier sense means that a device listens to see if the
bus is busy before it sends a message, just like you listen to make
sure a frequency is clear before you transmit.  If the bus is clear,
the device then sends its message.  Collision detection means that the
device listens to the bus while it is sending its message and compares
what it hears with what it put on the bus.  If the two are the same,
all is OK.  If they are different, it is because another device tried
to send a message at the same time.

If there was a conflict, or collision, the device deliberately sends a
jamming message to ensure that the other device, which is also
listening, senses the collision.  Next each device waits for a short
time, listens, and then tries to send the message again.  The waiting
times are randomized to minimize the chance of repeated collisions.

If a radio receives a valid command, it sends a positive reply message
to the computer that sent the command, telling it that the command was
received and executed.  If a radio receives an illegal command, it
sends a negative reply message to inform the sender that the radio
could not successfully execute the command.  Not all commands cause
the radio to generate positive or negative replies.  Some commands
simply request information from the radio, and the radio replies with
the requested information rather than a positive reply.  Two special
commands are provided that do not generate replies.

Not too many amateurs have more than one computer.  However, most hams
do have more than one radio, and ICOM's new interface bus is a simple
way to control several different radios with a single computer, using
only one interface connection to the computer.  Other manufacturers'
interfaces either require a separate connection to the computer for
each radio, or don't permit control of more than one radio of the same
type on a single bus.


PHYSICAL INTERFACE

Unlike the previous ICOM interface [4], the new ICOM CI-V system
requires no additional hardware inside the radios themselves.  The new
system uses the standard RS-232C format, with both the RS-232C
Transmit Data (TXD) and Receive Data (RXD) connected to the single
ICOM interface bus signal line to allow both transmitting and
receiving on the two-wire ICOM bus.

The interface runs at TTL (+5V and 0V) levels, so most computers will
need a simple voltage level converter to convert from the TTL levels
of the ICOM interface bus to the +12V and -12V levels used by standard
RS-232C serial ports.  ICOM doesn't currently make such a device, but
does include the schematic for a level converter in some of the
manuals.  Yaesu makes a level converter (the FIF-232C) and so does
Kenwood (the IF-232C).

A simple level converter that requires only a single +5V power supply
can be built using a single MAX-232 chip (from Maxim Integrated
Products, 510 N. Pastoria Ave., Sunnyvale, CA 94086).

The bus address and baud rate of the radios are selected by internal
jumpers.  The 735 has three bits of address, the R7000 has four bits,
and the 275 and 475 have seven.  Bus address 0 has a special meaning
and should not be assigned to a radio.  The 735, R7000, 275 and 475
come with their addresses set to 4, 8, 16 (hex 10) and 20 (hex 14),
respectively.  All the radios seem to come with their baud rate set to
1200 baud.  Baud rate for all can be set at either 300, 1200, or 9600
baud.  Data is sent using 8 data bits, no parity, and one stop bit.


COMMAND FORMAT

Commands (and replies) on the ICOM interface bus are sent in the form
of packets.  Yes, packets are everywhere these days.  These packets
aren't the same as the well-known AX-25 or TCP/IP packets used by ham
packeteers, but there are some similarities.

Each packet is a series of 8-bit bytes.  A diagram of a packet looks
like:

  FE FE destaddr srcaddr cmdcode [data1 data2 .... dataN] FD,

where

     FE FE               is the preamble,
     destaddr            is the bus address of the destination
                    device,
     srcaddr             is the bus address of the source
                    device,
     cmdcode             is the command code,
     data1 .... dataN    are the data bytes, and
     FD                  is the end byte.

The first two bytes (both hex FE) are a PREAMBLE, which signals the
start of a packet.  The third byte is the DESTINATION ADDRESS, which
tells which device the packet is intended for, and the fourth byte is
the SOURCE ADDRESS, which tells which device the packet is being sent
from.  Next comes the COMMAND CODE, followed by zero or more DATA
bytes.  Finally, an END byte (hex FD) indicates the end of a packet.

Packets vary in length from six to seventeen bytes.   An address can
be any 8-bit value except FD (FD is unusable because FD is used for
the end byte of a packet).  Computers can be assigned any unique
address except 0 and FD.  Address 0 is a special "broadcast" address
for Transceive Mode.

----------------------------------------------------------------

                       TABLE 1: COMMAND SUMMARY

COMMAND     FUNCTION           DATA BYTES      BYTES
 BYTE                             SENT        RETURNED

  0       Set Frequency         frequency    none
            (TX Mode)

  1       Set Mode (TX Mode)    mode         none

  2       Read Frequency        none         IC 275/475, IC735:
             Range                             lower [2D] upper
                                             R7000:
                                               upper [2D] lower

  3       Read Frequency        none         frequency

  4       Read Mode             none         mode

  5       Set Frequency         frequendy    FA/FB

  6       Set Mode              mode         FA/FB

  7       Set VFO               none/VFO     FA/FB

  8       Set Memory            memory       FA/FB

  9       Write VFO to Mem.     none         FA/FB

  A       Write Mem.to VFO      none         FA/FB

  B       Clear Current Mem.    none         FA/FB

  C       Read Current Offset   none         offset

  D       Set Current Offset    offset       FA/FB

  E       Start/Stop Scanning   start/stop   FA/FB

Note: Commands 0 through A are documented in information available
from ICOM.  Commands B through E are not currently documented, but
have been found to work on the IC275 and IC 475.

----------------------------------------------------------------


COMMANDS

Table 1 is a summary of the available commands.  Not all commands are
meaningful to all radios.  For example, the R7000 has 99 memories but
no VFO, and generates a negative reply to Commands 7 and A.


     DATA BYTES

Frequency:

Frequency data is packed two digits per byte, beginning with a (10Hz,
1Hz) byte.  The 275, 475 and 735 ignore the 1 Hz digit, and the R7000
ignores the 1 Hz and 10 Hz digits, but they must be sent nonetheless.
Only as many bytes as necessary need be sent.  For example, if the
highest digit to be changed is the KHz digit, only two bytes of
frequency data are needed.

     IC-735: 4 bytes
9         (e.g., 14.12345 is sent as 50 34 12 14)

     IC-275/475, IC-R7000: 5 bytes
          (e.g., 148.76543 is sent as 30 54 76 48 01).

Mode:

Modes can be designated by either one or two bytes.  The R7000 can
operate on either sideband, but selection is made by a switch on the
back panel.  Since there is no command that definitively sets an R7000
to USB or LSB, ICOM has used a different code for SSB on the R7000.

      IC735:           R7000:                IC275/475

     00 - LSB        02    - AM            00    - LSB
     01 - USB        05    - FM Wide       01    - USB
     02 - AM         05 02 - FM Narrow     03    - CW
     03 - CW         05 00 - SSB           03 02 - CW Narrow
     04 - RTTY                             05    - FM
     05 - FM

VFO:

VFO data is a single byte, either 0 for VFO A or 1 for VFO B.

Memory:

Memory data is a single byte containing the memory number.

Start/Stop Scanning:

A single byte.  A one starts scanning, a zero stops scanning.


     REPLY MESSAGES

Reply messages consist of a packet with a preamble, destination and
source addresses, a reply code, and an end byte.  The reply code is
either hexadecimal FA, a negative reply, or hexadecimal FB (cute,
huh?) for a positive reply.  Transcieve Mode commands do not cause the
radio to generate a reply.

A negative reply is returned by the radio to the computer whenever a
command is undecipherable or there is an error in the data inside the
packet, such as out-of-bounds frequency data, missing bytes, an
attempt to select a non-existent memory, an undefined command, etc.

A positive reply is returned by the radio to the computer after a
legal command is received and executed.  Inquiry commands which cause
the radio to send data back to the computer do not return a positive
reply, since the returned data itself serves as a positive reply.


     JAMMING SEQUENCE

When a radio is sending a message and detects a collision, it will
immediately stop sending.  In order to prevent the (somewhat unlikely)
case in which the collision merely corrupts the content of a message
without destroying its format, ICOM has implemented a jamming
sequence, which is:

     FC FC FC FC FC.

After detecting a collision, the radio immediately sends the jamming
sequence and then waits for a short randomized period of time before
it listens to the bus and tries to resend the message that was
involved in the collision.  The radio will repeat the process for up
to five times, but will then give up trying.


     TRANSCEIVE MODE (TX MODE)

This interface provides a new feature, called Transceive Mode (TX
Mode).  TX Mode allows two compatible radios to be connected so that
whenever the frequency or mode is changed on one radio the other
radio's frequency or mode will follow.  No computer is needed.  The
bus connector on the back of one radio is simply connected to the bus
connector on the back of the other.

Transceive Mode also allows a computer to monitor the current state of
a radio without the need to issue any commands.  This capability is
useful for logging purposes.

TX Mode is enabled and disabled by a switch on the same internal
switch block that controls the radio's address and baud rate.  If a
radio's TX Mode is enabled, then whenever the radio changes frequency
or mode, the radio itself will send a command that will cause the
other radio to change frequency or mode correspondingly.  All radios
examined thus far have come from the factory with TX Mode enabled.

If a radio's TX Mode is enabled, it will send a Command 0 (Set
Frequency) packet whenever it changes frequency and a Command 1 (Set
Mode) packet whenever it changes mode.  The destination address in
these packets is always 0, and the source address is the radio's own
address.

Any radio with TX Mode enabled will respond to Commands 0 and 1 if the
destination address is 0 or the radio's actual address.

A radio in TX Mode will not generate frequency and mode command
packets while it is scanning, but will generate both when it is
stopped from scanning.

When a radio receives a Command 0 packet, it DOES NOT reply with a
positive or negative reply packet.

While primarily designed to implement TX Mode,  Command 0 can be used
by a computer in place of Command 5 if no reply is desired.


     THE STRANGE CASE OF THE R7000

The behavior of the R7000 is a bit different than that of the 275 and
735, largely because it lacks the concept of VFO A and VFO B as
implemented in the other radios.  The following describes the known
peculiarities of the R7000.

An R7000 is capable of receiving signals at frequencies up to
1999.9999 MHz (except for 1000 to 1025 MHz).  Above 1 GHz, ICOM only
publishes and guarantees specifications within the 1240 to 1300 MHz
band.  Frequencies above 1 GHz are selected by a "1 GHz" switch on the
radio's front panel, which inserts a 1 GHz converter in the radio's
signal path.  The converter cannot be selected or deselected via the
computer interface, nor can the state of the "1 GHz" switch be sensed
through the interface.  If the "1 GHz" front panel switch is
depressed, all frequencies will be raised by 1 GHz.

The R7000 always replies to Commands 7 (Set VFO) and A (Write Memory
to VFO) with a negative reply message.  In the R7000, Command 8 (Set
Memory) causes the contents of the selected memory to be transferred
to the dial, causing the R7000 to jump to the frequency and mode
stored in the specified memory.  This is equivalent to selecting a
memory and writing it into the current VFO on the 275, 475 or 735.
Command 9 (Write VFO to Memory) causes the R7000 to write the current
frequency and mode as shown on the display into the selected memory.

When it is in TX Mode, the R7000 sends only a mode packet when its
mode is changed via the front panel, while the 275, 475 and 735 send
both frequency and mode packets when their mode is changed, even
though the frequency may not have changed.


SAMPLE BASIC PROGRAM

The sample Basic program runs under IBM BASIC or BASICA on the IBM PC,
and allows the user to set the frequency and mode of an R7000 from the
computer.  It has not been tested on any other computer or any other
version of Basic, but translating it to your computer's version of
Basic should not be too difficult.

The program reads back and prints back both the command that was sent
and the radio's reply.  However, the program doesn't compare the
command it sent out with what it heard on the bus, which would be
necessary if there were more than two devices on the bus.


IMPROVEMENTS OVER PREVIOUS COMMAND SETS

The new command set has some improvements over the command set for the
R71/751/271/471/1271 series.  You can now:

  o  Stop the radio from scanning (by issuing a Set Frequency command)
     and take control of the radio,

     If a radio receives a Set Frequency command while scanning, it
     will stop scanning and change to the specified frequency. If it
     receives any other command (legal or illegal) it will hold the
     command until scanning is stopped manually and will then process
     the command.

  o  Select which VFO to use, if the radio has more than one (this
     feature was possible on ICOM's second type of interface but
     missing from the third), and

  o  Monitor the radio's frequency and mode without issuing commands
     to the radio (using TX Mode).

  o  Clear memories.

  o  Set and read the radio's duplex offset.

  o  Start and stop scanning (on the 275 and 475).

However, the command set still lacks a number of features, as pointed
out in [4], such as setting or reading the RIT.  With the previous
ICOM interface, NG6Q was able to go a bit beyond the normal command
set and achieve a few additional functions by accessing "memories" 33
to 255 (the radios have only 32 memories).  The processors in the 275,
475, 735 and R7000 enforce memory and frequency limits more
rigorously, and the author has thus far been unable to "fudge" the
memory and frequency boundaries.


SUMMARY

The new ICOM CI-V interface makes it easy to control one radio with
one computer, and at the same time makes it possible to control more
than one radio with more than one computer.  The additional hardware
needed to connect the radio to the interface bus is simple and easy to
build.  Command set functionality is improved over the previous
interface.  Amateur radio operators, one of the most ingenious groups
around, should be able to think of many unique and interesting
applications using the new interface.


REFERENCES

[1] G. Williman, "A Three-Chip Microcomputer for Your Station," QST,
Aug. 82, p. 19 (describes the IC-701/211/245 interface).

[2] C. Terwilliger, "Computer Control of the IC-255A," QST, May 81, p.
30 (describes the IC-720/251/255/260/451 interface).

[3] L. Studebaker, "Simple, Low-Cost Computer Control for the ICOM IC-
720," QST, July 84, p. 34.

[4] R. Bisbey, "Computer Control of ICOM R-71, 271, 471 and 751
Radios," Ham Radio, April 86, p. 47.

[5] K. Strom, "A CAT Control System," QST, Oct. 85, p. 38 (describes
the Yaesu CAT interface system).

[6] C. Bahr, "Simple ICOM IC-735 to C-64 Interface," Ham Radio, March
87, p. 39.


APPENDIX (OR SIDEBAR) 1 - SAMPLE BASIC PROGRAM

10 ' This sample program is written in IBM PC Basic, and sets the
20 ' mode and frequency of an ICOM R7000.  The mode must be AM, FMW,
30 ' FMN, FM, or SSB, and the frequency must be between 25 and
40 ' 999.9999 MHz.

50 OPEN "COM2:1200,N,8,1" AS #1         ' Author's setup uses COM2:
60 INPUT "FREQUENCY,MODE";F,M$          ' Get frequency, mode

100 ' This section looks for mode = "AM", "FMW", "FMN", "FM", or "SSB",
110 ' complains if it doesn't find it, and otherwise assembles the
120 ' data string for the mode command.
130 IF (M$="AM") THEN MO$=CHR$(&H02): GOTO 200
140 IF (M$="FMW") THEN MO$=CHR$(&H05): GOTO 200
150 IF (M$="FMN") OR (M$="FM") THEN MO$=CHR$(&H05)+CHR$(&H02): GOTO 200
160 IF (M$="SSB") THEN MO$=CHR$(&H05)+CHR$(&H00): GOTO 200
170 PRINT "Unknown mode "; M$; " Please try again": GO TO 60

200 ' This section checks the frequency to make sure it is in bounds,
210 ' objects if it isn't, and otherwise assembles the proper data
220 ' string for the frequency command
230 IF (F>=25) AND (F<1000) GOTO 250    ' Bounds check
240 PRINT "Out-of-bounds frequency"; F; "Please try again": GO TO 60
250 F$=STR$(F)                          ' Make a string out of it
260 F$=MID$(F$,2,LEN(F$)-1)             ' Eliminate leading space
270 IF (F<100) THEN F$="0"+F$           ' Add leading zero if needed
280 FOR I=1 TO 5: F$=F$+"0": NEXT I     ' Add trailing zeros
290 FR$=CHR$(0)                         ' Format for ICOM
300 FR$=FR$+CHR$(16*VAL(MID$(F$,7,1))+VAL(MID$(F$,8,1)))
310 FR$=FR$+CHR$(16*VAL(MID$(F$,5,1))+VAL(MID$(F$,6,1)))
320 FR$=FR$+CHR$(16*VAL(MID$(F$,2,1))+VAL(MID$(F$,3,1)))
330 FR$=FR$+CHR$(VAL(MID$(F$,1,1)))

400 ' Here is the main part of the program
410 DA=8                                ' Destination address (R7000)
420 SA=&HF1                             ' Source address (IBM PC)

500 ' Send the Set Mode command and look at the command and reply
510 CM=6                                ' Set Mode command code
520 DA$=MO$                             ' Mode data
530 GOSUB 1000                          ' Send the command
540 GOSUB 2000                          ' Print out command heard
550 GOSUB 2000                          ' Print out reply heard

600 ' Send the Set Frequency command and look at the command and reply
610 CM=5                                ' Set Frequency command code
620 DA$=FR$                             ' Frequency data
630 GOSUB 1000                          ' Send the command
640 GOSUB 2000                          ' Print out command heard
650 GOSUB 2000                          ' Print out reply heard

700 CLOSE #1
710 END

1000 ' Command sending subroutine
1010 PRINT #1,CHR$(&HFE);CHR$(&HFE);    ' Preamble
1020 PRINT #1,CHR$(DA);                 ' Destination address
1030 PRINT #1,CHR$(SA);                 ' Source address
1040 PRINT #1,CHR$(CM);                 ' Command code
1050 PRINT #1,DA$;                      ' Data
1060 PRINT #1,CHR$(&HFD);               ' End byte
1070 RETURN

2000 ' Monitor command or reply and print it out
2010 A$=INPUT$(1,#1)                    ' Get next character
2020 V=ASC(A$)                          ' Convert to number
2030 H$=HEX$(V)                         ' Convert to hex string
2040 PRINT H$;                          ' Print it out
2050 PRINT " ";
2060 IF V=&HFD THEN GOTO 2080           ' Look for end byte
2070 GOTO 2010                          ' Loop back for next char
2080 PRINT
2090 RETURN
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